Microwave pyrolysis reactor

Abstract

The present invention provides a microwave pyrolysis reactor ( 1 ) comprising an inner pipe element ( 2 ) and a housing ( 4 ), wherein the inner pipe element ( 2 ) is made of a microwave transparent material and comprises a first open end ( 5 ) and a second open end ( 6 ); the housing ( 4 ) comprises a first inner surface, enclosing an annular space ( 7,44 ) around the inner pipe element ( 2 ), a waste inlet ( 10 ), a solids outlet ( 11 ), a gas outlet ( 12 ), an inert gas inlet ( 45 ) and a port ( 13 ) for a microwave waveguide ( 14 ), the waste inlet and the solids outlet are in communication with the first open end and the second open end of the inner pipe element, respectively, and the port for a microwave waveguide is in communication with the annular space; and wherein the inner pipe element is arranged with the first open end at a higher vertical level than the second open end, such that a material entering the waste inlet during use is transported through the inner pipe element, from the first open end to the second open end, by gravity; and wherein the gas outlet ( 12 ) is arranged upstream the first open end of the inner pipe element and downstream the waste inlet of the housing, and the inert gas inlet ( 45 ) is arranged to provide an inert gas into the annular space ( 7,44 ) during use.

The invention claimed is: 
     
       1. A microwave pyrolysis reactor ( 1 ) comprising an inner pipe element ( 2 ) and a housing ( 4 ), wherein
 the inner pipe element ( 2 ) is made of a microwave transparent material and comprises a first open end ( 5 ) and a second open end ( 6 ); 
 the housing ( 4 ) comprises a first inner surface, enclosing an annular space ( 7 , 44 ) around the inner pipe element ( 2 ), a waste inlet ( 10 ), a solids outlet ( 11 ), a gas outlet ( 12 ), an inert gas inlet ( 45 ) and a port ( 13 ) for a microwave waveguide ( 14 ), the waste inlet and the solids outlet are in communication with the first open end and the second open end of the inner pipe element, respectively, the gas outlet ( 12 ) is in fluid communication with the inner pipe element, and the port for a microwave waveguide is in communication with the annular space; and 
 
       wherein the inner pipe element is arranged with the first open end at a higher vertical level than the second open end, such that a material entering the waste inlet during use is transported through the inner pipe element, from the first open end to the second open end, by gravity; and 
       wherein the inert gas inlet ( 45 ) is arranged to provide an inert gas into the annular space ( 7 , 44 ) during use; and 
       wherein the inner pipe element ( 2 ), together with the waste inlet ( 10 ) and the solids outlet ( 11 ), is part of a conduit ( 37 ) not in fluid communication with the annular space ( 7 ,  44 ) around the inner pipe element ( 2 ). 
     
     
       2. The microwave pyrolysis reactor according to  claim 1 , comprising a waste inlet assembly ( 20 ) in communication with the waste inlet ( 10 ) and arranged to provide a material to be pyrolyzed to the first open end of the inner pipe element in a gastight manner, and a solids outlet assembly ( 22 ) in communication with the solids outlet ( 11 ) and arranged to allow a material to exit the microwave pyrolysis reactor in a gastight manner. 
     
     
       3. The microwave pyrolysis reactor according to  claim 2 , wherein at least one of the waste inlet assembly and the solids outlet assembly comprises a waste inlet chamber ( 20 ) and a solids outlet chamber ( 22 ), respectively. 
     
     
       4. The microwave pyrolysis reactor according to  claim 3 , wherein each of the waste inlet chamber and the solids outlet chamber comprises a first valve ( 25 , 29 ) and a second valve ( 26 , 30 ) for isolating the respective chamber. 
     
     
       5. The microwave pyrolysis reactor according to  claim 4 , wherein each of the waste inlet chamber and the solids outlet chamber comprises a gas inlet ( 27 ) and a gas outlet ( 28 ) for inert gas purging of the respective chamber. 
     
     
       6. The microwave pyrolysis reactor according to  claim 1 , comprising a pressure sensor ( 43 ) for monitoring the pressure within the annular space ( 7 , 44 ). 
     
     
       7. The microwave pyrolysis reactor according to  claim 1 , wherein the gas outlet ( 12 ) is connectable to a gas treatment system ( 47 ) comprising a suction device ( 48 ), such that a below ambient pressure may be present at the gas outlet during use. 
     
     
       8. The microwave pyrolysis reactor according to  claim 1 , wherein the inert gas inlet ( 45 ) is connectable to an inert gas source ( 46 ), such that an inert gas of at least ambient pressure may be present in the annular space ( 7 , 44 ) during use. 
     
     
       9. A waste treatment system comprising a microwave pyrolysis reactor according to  claim 1 , a microwave source ( 49 ), a gas treatment system ( 47 ) and an inert gas source ( 46 ); wherein
 the microwave source ( 49 ) is connected to the port ( 13 ) by a microwave waveguide ( 14 ); 
 the gas treatment system ( 47 ) is connected to the gas outlet ( 12 ) and comprises a suction device ( 48 ) arranged such that the pressure at the gas outlet ( 12 ) may be kept below ambient pressure during use; and 
 the inert gas source ( 46 ) is connected to the inert gas inlet ( 45 ), such that an inert gas of at least ambient pressure may be present in the annular space ( 7 , 44 ) during use. 
 
     
     
       10. A method of monitoring the structural integrity of a microwave pyrolysis reactor, wherein the reactor comprises an inner pipe element ( 2 ) made of a microwave transparent material and a housing ( 4 ); the housing encloses an annular space ( 7 , 44 ) around the inner pipe element ( 2 ) and comprises a gas outlet ( 12 ) in fluid communication with the inner pipe element, an inert gas inlet ( 45 ) in fluid communication with the annular space, a waste inlet ( 10 ) and a solids outlet ( 11 ), wherein the inner pipe element ( 2 ), together with the waste inlet ( 10 ) and the solids outlet ( 11 ), is part of a conduit ( 37 ) not in fluid communication with the annular space ( 7 ,  44 ) around the inner pipe element ( 2 ), and the method comprises the steps of:
 applying suction to the gas outlet ( 12 ) to obtain a below ambient pressure inside the inner pipe element ( 2 ); 
 introducing an inert gas to the annular space via the inert gas inlet ( 45 ) to obtain an ambient, or above ambient, pressure in the annular space; 
 monitoring the pressure in the annular space during a pyrolysis reaction inside the inner pipe element.